Valve service boxes, commonly known as curb boxes, are well known in the art. Modern valve boxes are generally fabricated of some suitable plastic such as either a filled or unfilled ABS. The upper portion comprises generally a pair of telescoping tubular members, the lower member of which terminates in a valve housing. A typical such valve service box is illustrated in U.S. Pat. No. 3,601,143.
With the advent of plastic pipe certain problems have arisen which were not experienced earlier with metal pipe. The valve body is ordinarily engaged to the pipe by some suitable threaded fitting. When fittings on opposite sides of the valve are tightened to secure the pipe segments thereto, internal stresses in the pipe are gradually and spontaneously relieved by counter rotation of the pipe. This rotation is transferred to the valve body displacing it from its normal vertical orientation. This, in turn, displaces the valve operating member from the vertical plane sometimes sufficiently to prevent its actuation from the surface.
Therefore, it is desirable to provide means on the curb box engageable with the valve housing to restrict its rotational displacement under the influence of relieving stresses in the pipes to which it is engaged. One such means are a pair of diametrically opposed openings in the housing portion of the valve service box. Each opening is non-circular and is shaped and dimensioned to conform with a complimentary non-circular portion of the valve body or fitting associated therewith which is employed to join the valve body to the pipe. The bottom-most portion of the non-circular opening in the housing communicates with a preferably outwardly and downwardly flaring opening communicating with the bottom edge of the housing. The housing is sufficiently flexible to permit the valve body to pass upwardly through the flared portion of the opening and snap-engage into the non-circular portion thereof.
Another problem recently encountered in the art arises by virtue of the fact that different sized valves are now being employed for use with the same sized pipe. Consequently, housings had to be custom fitted to the particular sized valve being employed which is economically inefficient.
An obvious solution to the problem of different sized in a valve housing to accommodate at least two different sized valves. However, the use of two opposed pairs of openings so weakened the valve housing structurally that it tended to distort and thereby defeat the purpose of the non-circular openings to hold the valve body in its desired vertical orientation. The best solution to this problem does not lie in making the walls of the housing thicker and stronger which would greatly increase costs with only a marginal improvement in structural strength.
The solution lies in the structural features of the claimed invention herein which employs a cover which preferably overlies each opening and which may be easily detached therefrom. When in use, the covers overlying the openings to receive the valve are detached but the covers on the other pair of opposed openings are left in place. These covers provide bearing surfaces or fill around the housing which bearing surface transmits the lateral forces of the fill to the housing as a whole thereby generating the requisite structural rigidity necessary to prevent undesired rotation of the valve body.
Preferably, the covers are formed integrally with the molded housing and are partially severed from the bottom edge of the housing upwardly requiring but a small saw cut for complete removal. This provides for attachment of the covers until such time as the user decides which pair of opposed valve openings is to be employed. Additionally, when the cover is formed as part of an outwardly extending flange defining the opening, pressure is transmitted from the cover to the flange and from thence to the housing body as a whole. With the cover being formed integrally with the top portion of the non-circular opening, the cover is structurally relatively rigid and undeformable in response to lateral stress applied by backfill.
Still another object of the present invention is to provide opposed pairs of outwardly and downwardly flaring bearing surfaces proximal to the top of the openings, preferably formed integrally with the housing on the tubular member extending therefrom which surfaces modify forces applied by backfill to the housing thereby increasing its structural integrity as well as generating additional vertical restraining forces against upward undesirable displacement of the housing as a whole.